Explanation:
The total phase of the
June 15 lunar eclipse
lasted an impressive 100 minutes.
Its entire duration is covered in
this composite of a regular sequence of digital camera exposures,
tracking the dark lunar disk as it
arced above the Acropolis in Athens, Greece.
In fact, around 270 BCE Greek astronomer
Aristarchus
also tracked the duration of lunar eclipses, though without
the benefit of digital clocks and cameras.
Still,
using geometry, he
devised a simple and impressively accurate way to calculate
the Moon's distance, in terms of the radius of planet Earth,
from the eclipse duration.
A more modern Greek astronomer,
Elias Politis titled this eclipse duration study
and the accompanying youtube timelapse
video "Acropoclipse".